A wiring box including a lid body which opens and closes an opening for wiring, which vertically penetrates through a top plate of a table, is known. The wiring box is mounted to the lower surface of the top plate, and a duct at the lower portion of the wiring box can accommodate power supply devices such as sockets, LAN cables, and the like. In addition, during a work on the top plate using a notebook PC or the like, it is configured to use the socket or the like accommodated in the duct at the lower surface of the top plate via the opening of the top plate.
In addition, the lid body of the wiring box is configured to be selectively opened and closed between a state of closing the opening and a state of opening the opening. Particularly, in the open state of the opening, it is configured to accommodate the lid body inside the wiring box (for example, Patent Literature 1).
As such, the wiring box is configured to be fallen into the opening from above the top plate, and a flange formed in the periphery of the wiring box is caught on the edge of the opening so that positioning of the lid body of the wiring box and the surface of the top plate of the table in the height direction is performed.
In this case, while positioning of the wiring box can be easily performed, the flange in the periphery of the wiring box protrudes from the surface of the top plate and thus there is a problem in that the surface of the top plate is not flat in use (for example, Patent Literature 2). Here, providing a height difference of the height of the flange of the wiring box in the periphery of the opening may be considered. However, molding the periphery of the opening of the top plate becomes complex and thus there is concern that excess cost may be needed (for example, Patent Literature 3)
Therefore, in order to allow the surface of the top plate to be flat in use, a method of inserting the wiring box from below the opening without the use of a hooking member such as a flange may be considered. However, there is a problem of how to enable the upper surface of the lid body of the wiring box to be flush with the surface of the top plate in a case where the top plate with a different thickness is used.
That is, while the thickness of the top plate varies depending on the types of the table, in order to allow a height between the lid body and a mounting metal fitting of the wiring box to be constant, the height of the mounting metal fitting of the wiring box needs to be changed according to the thickness of the top plate. Otherwise, there is also a method which employs mounting metal fittings having an adjusting mechanism corresponding to each top plate thickness. However, a mounting process requires labor, and there is a problem in terms of a selection of components and cost.